Accident Analysis cont'd - DOE-STD-1120-1-20050036

DOE-STD-1120-2005/Vol. 1

requires the use of pre-negotiated step-out criteria that are reviewed and approved by DOE

during the DSA review process. Stepping-out of a control does not necessarily mean that the

control may be de-energized, as it still may be needed to satisfy life safety or emergency

response requirements. It simply means that a control be retired from the safety basis.

Once the criteria are satisfied, only contractor verification that the condition is met, and that

DOE is notified, is necessary to allow the contractor to retire the control. When using this

approach, the DSA should use explicit terms and conditions that define the conditions and

process for retiring controls, and provide administrative controls that describe the process for

stepping out of a control, as well as further safety measures if necessary, once a control is retired

(e.g., increased fire watch or lower combustible limits).

4-9